In many wireless communication network protocols, uplink communications—from mobile User Equipment (UE) to fixed network transceivers (e.g., NodeB)—are explicitly scheduled by network controllers. However, the UE may not always have uplink data packets ready to transmit. For example, a UE based user may be engaged in a voice call with a fixed network based user where the speech service is implemented by packet data transfers, such as Voice over Internet Protocol (VoIP). If the UE based user is listening to the other party (i.e., receiving data packets containing speech information on the downlink) and not speaking, the UE will typically not have any data packets to transmit to the network on the uplink since both users will not typically speak simultaneously. If a network controller has allocated the UE a transmission opportunity on a shared uplink channel—for example, a time slot on an uplink frequency allocated to one or more UEs by the network—the transmission opportunity will go unutilized if the UE has no data packets to transmit. If other mobile UEs served by the same network controller and having been allocated the same shared uplink channel, have data packets to transmit, the failure of a specific UE to utilize its allocated transmission opportunity reduces overall uplink bandwidth utilization and represents a waste of limited air interface resources.